Cindy Caldwell, Master Gardeners of Placer County
From The Curious Gardener, Spring 2008
Lilacs (Syringa spp.) are renowned worldwide for their springtime fragrance and beauty. Native to Eastern Europe, they have been a valuable addition to gardens throughout Europe, Asia and America for hundreds of years.
They are so popular in fact, that every year lilac festivals are held around the world. One festival in Highland Park, New York has over 500 varieties of lilacs and draws over 500,000 visitors per year. There are more than 2000 varieties of lilacs in existence. With a color palate including white, pink, rose, lavender, magenta, blue, and (of course) lilac, they offer beautiful conical panicles of flowers, usually very fragrant. Lilacs bloom for 4 to 6 weeks in April or May, although some varieties wait for early summer.
Lilacs are deciduous and can take the form of either tall shrubs or small trees. They prefer fertile, humus rich, neutral to alkaline soil, and they need good drainage.
Water deeply once a week in spring and twice a week in summer, and plant in full sun, although they should be protected from reflected heat.
Lilacs bloom on second year growth, so after the first two years, cut back the shoots 20% to 40%, to a pair of opposite nodes. After 3 years, prune in early winter to remove wayward or crossing shoots, maintaining a healthy framework and removing the oldest branches. Most lilacs require a good winter chill (approx. 1 1⁄2 months of less than 45 degrees Fahrenheit) to bloom abundantly and are hardy to 0 degrees Fahrenheit. Depending on your location and elevation, you may not have the winter chill that most lilacs require, but fear not! Growers around the world have hybridized lilacs that will bloom beautifully even in warmer winter climates.
Lilacs are susceptible to powdery mildew, verticillum wilt, bacterial leaf spot and anthracnose. Borers, scale, leafminers and caterpillars may find your lilac attractive.
To propagate, plant seeds in containers in spring, or you can take softwood cuttings or propagate by layering in early summer.
Syringa vulgaris provides a good parent stock for hybridizing other lilacs like S. oblata (a Chinese species) to yield S. hyacinthiflora, a group of hybrids that bloom earlier than common lilacs and have some improved landscape traits. A few varieties worth mentioning are: ‘Asssessippi’ (a compact, fragrant, single lavender) that needs little pruning, ‘Excel’ (a double-flowered lilac color with strong fragrance), ‘Mount Baker’ (a single white) and ‘Sensation’ (a single wine red, with white edges).
There are some lovely compact varieties like ‘Miss Kim’ (S. pubescens patula) with ice blue flowers from deep purple buds, intensely spicy perfume and burgundy foliage in the fall. It will grow to 10’ tall and wide, as will Persian lilacs (S. persica) with deep purple flowers. A smaller variety is ‘Palibin’ (S. meyeri), a dwarf Korean lilac that only reaches 3-4 feet with purple flowers.
On the opposite spectrum, tree lilacs can reach up to 30’ tall, like the Japanese tree lilacs (S. reticulata) with form similar to apple trees with creamy white flowers, blooming in early to mid summer. ‘Ivory Silk’ will reach up to 20’ and flowers profusely, even when young.
So, join the fan club! Lilacs offer such a wide variety of colors, sizes, and environmental requirements, everyone can enjoy their beauty and their sensational scent of spring.
References
Encyclopedia of Garden Plants. 1996 The American Horticultural Society, Christopher Brickell, Judith D. Zuk, Editors- in-Chief
“Lilacs” by Michelle Le Strange UC Master Gardener Advisor, Tulare/ Kings County
http://cetulare.ucdavis.edu/ MG/ARTICLES/N022306.htm
“Choosing a Lilac, Planting a Lilac & Collections.” International Lilac Society, www.internationallilacsociety.org
Ornamental Plants—Their Care, Use, Propagation and Identification. Revised Edition 1994 By D. Dwight Wait
Pests in Gardens and Landscapes, “Syringa, Lilac, Japanese tree lilac- Syringa spp.” www.ipm.ucdavis.edu